What does validity in testing measure?

Validity in testing is fundamentally about the extent to which a test accurately measures what it is intended to measure. This means that if a test is designed to assess a specific construct, such as musical ability or emotional intelligence, validity ensures that the test genuinely reflects that construct rather than something else.

For instance, if a music therapy assessment is aimed at evaluating a client's therapeutic progress through musical engagement, validity would ensure that the assessment effectively captures aspects of that engagement and not unrelated factors. High validity indicates that the test can provide meaningful, accurate results that can inform treatment decisions and interventions.

While aspects like consistency over time (reliability), comparisons to norm groups (norm-referenced scoring), and the subject matter knowledge of test-takers are important considerations in testing, they pertain to other dimensions of measurement. Reliability addresses consistency, norm referencing relates to benchmarking against others, and subject matter knowledge focuses on the background of the test-takers rather than the construct being measured itself.